Trick files are precompiled files used in narrowcast systems to implement trick mode playback such as fast-forward and rewind in an efficient fashion. Fast-forwarding and rewinding are generally accomplished by playing precompiled trick files at normal speed in place of the normal playback file. The known technique of playing the normal playback file at a higher rate of speed utilized by devices such as cassette players and VCRs is not an ideal or efficient choice when servicing multiple users, since it places significantly higher demands on the components in the system. Instead, the trick files are played at normal speed but appear to be at a different speed because the trick files are composed of a subset, for example every other complete frame, of the normal file. The dominant narrowcast application is the delivery of content on demand (COD). This content may span many categories, including movies on demand (MOD), video on demand (VOD), subscription video on demand (SVOD), free on demand (FOD) and network-based digital video recording (NDVR).
Narrowcast programming is point-to-point streaming of video from a storage point in the network to a specific subscriber. Narrowcast applications are made possible by compression techniques, e.g., the standards developed by the Moving Picture Experts Group (MPEG), that enable more content to be delivered to viewers with little or no degradation in picture quality. The resulting increase in transmission capacity allows narrowcast programming to be placed alongside broadcast programming for delivery to viewers.
Narrowcast applications are further enabled by the installation of digital television networks that enable two-way communication so that a subscriber can interact or “request” information from the network equipment. A standard example of such interaction is a request to fast-forward or rewind a piece of content being viewed. This interactivity is an essential feature of interactive narrowcast applications.
However, when allowing fast forwarding or rewinding of recorded content that includes advertisements and other advertisement content (“advertisements”), the advertisements are effectively lost because current COD implementations are oblivious to advertisements. The COD system will generate trick content in normal fashion, i.e., selecting certain frames for inclusion in the precompiled trick content. As a result, the advertisements may be represented by a subset of video frames that are not indicative or typical of the advertisement. This is problematic because playing content without the proper advertisements may upset the revenue model for the cable companies or violate contractual obligations with advertisers.
Thus, there is a need to allow customers unhindered navigation through COD material (i.e., fast-forward and rewind) while maintaining the effectiveness of advertisements encountered during trick plays or to, alternatively, insert new advertisements into the trick content.